EPANET Export/Import of WaterCAD

Question

Hi! 
 I've exported a model from WaterCAD to EPANET .INP file. It seems like the [OPTIONS] the default flow unit is LPS no matter what my setting are in WaterCAD. The strangest thing is, that if I import it back to WaterCAD, Coordinate and Elevation units (and only these two) get reset to FEET, which is odd, considering that litre is SI related. If I change the units setting of the .inp file to CMH(m3/h), then the coordinate and elevation units stay set to meter. 
 Is this a known issue, or are there some options I might have missed before exporting to .INP? 
 Best regards,

Wayne Hartell · Accepted Answer

Hi Attila, 
 
Welcome back to the forums. 
 
Regarding the unit system used to export to EPANET, as you may know, EPANET supports two unit systems, that are determined by the flow units that are used. If the flow units are an SI unit, then the other units used in EPANET must be a set of fixed SI units. If the flow units are US customary, then the other units used in EPANET must be a set of fixed US Customary units. 
 
In WaterCAD and WaterGEMS we support the notion of different unit systems, allowing new models to be created in a consistent set of either SI or US Customary units, however, we don't require a particular set of units, nor do we require that models continue to use any particular unit for any particular field. Users may use a mix of SI and US customary units if they see fit. 
 
With the above in mind, we had to make a decision about how to determine which EPANET compatible unit system to use when processing exports. We could have elected to use one of a number of determining factors, but elected to determine this based upon the unit in use for the Coordinate field (i.e., the unit of distance that is used to represent the model map). If this unit is an SI unit, then the EPANET export will occur in SI units. If the coordinate unit is a US customary unit, then the EPANET export will occur in US customary units. Always for flow units, we use either LPS (SI) or GPM (US) as the flow unit. 
 
I also note your further post about the issue re-importing the exported INP file back into WaterCAD. The export and import operations should be completely independent of locale settings, so I tried this out and was able to hit the same problem as that which you report. I have developed a fix for this problem and will work with our people in technical support to provide you with a patch that should resolve the issue for you. 
 
Kind Regards, 
Wayne.